Electric switch assembly for control stations having rectilinearly or rotatably movable switch operators located at different centers

ABSTRACT

An electrical switch assembly having its component parts arranged so a maximum number of the common parts can be used in a flush mounted control station or a surface mounted control station with either of the control stations having rectilinearly moving or rotatable switch operators. The assembly includes components which operate on selected centers so the components may be selectively arranged to be used with two different switch covers, two different type switch actuators and with or without a pilot light. The components also are arranged so the rectilinearly movable operators may be interlocked or made to operate alternately and the rotary operator to be programmed to operate in a two or three position mode of operation.

United States Patent 1 Kiessling May 15, 1973 [541 ELECTRIC SWITCH ASSEMBLY FOR CONTROL STATIONS HAVING RECTILINEARLY OR ROTATABLY MOVABLE SWITCH OPERATORS LOCATED AT DIFFERENT CENTERS Rudolf H. Kiessling, Milwaukee, Wis.

Inventor:

2,969,418 1/1961 Benander ..l74/53 Primary Examiner-Robert K. Schaefer Assistant ExaminerWilliam J. Smith Attorney-Harold J. Rathbun et al.

[5 7] ABSTRACT An electrical switch assembly having its component parts arranged so a maximum number of the common parts can be used in a flush mounted control station or a surface mounted control station with either of the control stations having rectilinearly'moving or rotatable switch operators. The assembly includes com ponents which operate on selected centers so the components may be selectively arranged to be used with two different switch covers, two different type switch actuators and with or without a pilot light. The components also are arranged so the rectilinearly movable operators may be interlocked or .made to operate alternately and the rotary operator to be programmed to operate in a two or three position mode of operation.

18 Claims, 48 Drawing Figures [52] U.S. Cl. ..200/168 R, 174/53 [51] Int. Cl. ..H01h 9/02 [58] Field of Search ..200/l68 R, 168 B, 200/168 C, 168 D, 153 G; 174/53, 55, 66, 56

[56] References Cited UNITED STATES PATENTS 2,506,212 5/1950 Grohsgal 174/53 IOOg f IOOb PATENTEDHAY 1 51915 a; 733 ,451

SHEET 1 OF 6 PATENTED 3.733.451

FIG.3

2 FIG.33 FIG. 34

FIG. 35

PATENTED MAY 1 51973 SHEET 6 or 5 FIG. 23

FIG.29 F|G.3O

1 ELECTRIC SWITCH ASSEMBLY FOR CONTROL STATIONS HAVING RECTILINEARLY OR ROTATABLY MOVABLE SWITCH OPERATORS LOCATED AT DIFFERENT CENTERS This invention relates to manually operated electric switches and is more particularly concerned with a switch structure which may be used with two different type switch covers with the covers having unequally spaced openings and with the switch structure having either a rectilinearly movable or a rotatable operator which extends through the openings in the covers.

Surface mounted and flush mounted control stations are frequently used with magnetic motor starters to govern the starting, stopping or reversing of all types of electric motors. Because control stations are used in a large variety of different installations and are required to provide a variety of different switching functions, manufacturers of control stations are required to furnish control stations having push button operators, selector switch operators and pilot lights.

Flush mounted control stations are commonly installed in walls of buildings and include a conventional receptacle and an ornamental cover plate for the receptacle. The dimensions of the receptacle and cover plate have standardized by the electrical industry and require that a pair of openings in the cover plate for the operators for a switch mechanism mounted within the receptacle be located on centers one inch apart and be circular to accept cylindrical push buttons having a diameter of five-eighths inches.

While the use of flush mounted control stations in buildings has been accepted, their use in factories and machines and in pendant control installations to control the operation of machines and hoists is objection able because the relatively small size and close spacing of the operating buttons causes the operation of the control station to become more difficult when an attempt to operate the control station is made by a person wearing gloves. Accordingly, surface mounted control stations, which are intended for use in factories, are furnished with operating buttons which are spaced and have surface areas designed so that they can be conveniently operated by persons wearing gloves. Thus surface mounted control stations have larger operating buttons which are spaced further apart than the buttons in flush mounted control stations.

Conventional surface mounted and flush mounted control stations may have either a pair of push buttons or a rotary selector switch and may or may not include pilot lights. The push buttons of the control stations may or may not be interlocked and may be interlocked so that the pair of push buttons are maintained in their latest operated positions. The rotary selector switch may have either two or three indexed operating positions. The contacts within the switches operated by the push buttons or selector switch may be of the normally open or normally closed type. The control stations may be mounted in either a horizontal position or a vertical position requiring that the information, such as ON and OFF on the push buttons and selector switch, be properly oriented when the control station is mounted in either a vertical or horizontal position and finally it is desirable that the control station components be arranged so the control station may be conveniently mounted, wired and serviced without disturbing the wiring after the control station has been wired.

The present invention is directed to a switch structure which will permit the same switch housing to guide the movement of a pair of rectiline'arly movable contact carriers or a rotatable contact carrier and position a pilot light and the contact carriers so the switch structure may be used in either a flush mounted or a surface mounted control station. The structure further is arranged so that the same member, when positioned in the housing, may be used to provide the push button type control station with a maintained push button function or an interlocked push button function.

It is an object of the present invention to provide a switch assembly which has its component parts constructed and arranged so a maximum number of parts are common in all versions of a flush mounted and a surface mounted control station.

An additional object is to minimize the number of individual component parts required to provide all versions of a flush mounted and surface mounted control station.

Further objects and features of the invention will be readily apparent to those skilled in the art from the following specification and from the appended drawings illustrating certain preferred embodiments, in which:

FIG. 1 is a front plan view of a surface mounted control station when mounted in a horizontal position.

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1 when the control station is mounted in a vertical position.

FIG. 3 is an end view of the control station in FIG. 1 taken in the direction of the arrow 3.

FIG. 4 is a front plan view of a housing for a switch assembly as used in the control station in FIG. 1.

FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4.

FIG. 6 is a front plan view of a flush mounted control station with a cover for the control station removed.

FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6 with the cover secured to the control station.

FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6.

FIG. 8A is a plan view of a movable contact carrier.

FIG. 9 is a crosssectional view of an operating button for the control station in FIG. 6.

FIG. 10 is a rear view of the button in FIG. 9.

FIGS. 11 and 12 are front and side plan views of .an insert for the button in FIG. 9.

FIG. 13 is a cross-sectional view of the switch assembly as used in the'control station in FIG. 1 with the components of the switch arranged so the switch assembly will provide a momentary contact operating action and prevent the simultaneous operation of both operating buttons of the switch.

FIG. 14 is a front plan view of the switch assembly in FIG. 13 with the switch operating buttons removed.

FIG. 15 is a front plan view of a 3 unit surface mounted control station with the lens and bulb for a pilot light and an insert for one of the operating buttons removed.

FIG. 16 is a cross-sectional view taken along line 16-16 in FIG. 15 with the switch assembly including components which will interlock the switch buttons and cause the switch to provide a maintained contact function.

FIG. 17 is a cross-sectional view taken along line 17-17 in FIG. 15.

FIG. 18 is a cross-sectional view taken along line 18-18 in FIG. with the pilot light lens and bulb installed.

FIG. 19 is a front plan view of a surface mounted control station including a selector switch and a pilot light.

FIG. 20 is a cross-sectional view taken along line 20-20 in FIG. 19 with the base of the control station removed.

FIGS. 21B-D are front plan views of indexing plates and FIG. 21A is a front plan view of a cover plate as may be used with the switch assembly according to the present invention.

FIG. 22 is an exploded view showing in perspective the components of a rotary operator for the switch in FIG. 23 is a front plan view of a flush mounted control station with portions of the cover broken away and a rotary knob for a selector switch and portions of a pilot light assembly removed.

FIG. 24 is a cross-sectional view of the control station in FIG. 23 with the pilot light and knob installed in the assembly and a terminal block for the assembly removed.

FIG. 25 is a cross-sectional view taken along line 25-25 in FIG. 23 when the switch assembly is detached from the control station.

FIG. 26 is an enlarged plan view showing the front of an operating and indexing mechanism as used in the switch assembly in FIG. 23.

FIG. 27 is a cross-sectional view taken along line 27-27 in FIG. 26.

FIG. 28 is a rear plan view of an operator as used in the assembly in FIG. 27.

FIGS. 29 and 30 respectively are front and rear plan views of the knob used in the switch assembly in FIGS. 19 and 24.

FIGS. 31B-D are front plan views of different supports for a pilot light, and FIG. 31A is a view of a guide for a cylindrical button as may be used with the switch assembly according to the present invention.

FIGS. 32, 33, 34 and 35 respectively are front, rear and side plan views of aguide plate as used in a selector switch version of the switch assembly according to the present invention.

FIGS. 36 and 37 are respectively rear and end plan views of a legend plate as used in the control station in FIG. 19.

FIGS. 38 and 38A are rear and side plan views of a pilot light socket as used in the control stations in FIGS. 20 and 24.

FIG. 39 is a cross-sectional view taken along line 39--39 in FIG. 38, and

FIG. 40 is a front plan view of a housing for a switch assembly as used in the control station in FIG. 15 as mounted adjacent a broken-away portion of the housing shown in FIG. 4.

A surface mounted control station 10, as shown in FIGS. 1-3, includes a metal base 12 and a cover 14. The base 12 has a rear wall 16 and end walls 18 at the opposite ends of the rear wall 16. The rear wall 16 is provided with openings, not shown, which are used to secure the control station 10 to a support and each of the end walls 18 is provided with a conventional knockout 20 which may be removed when an electric conduit is connected to the control station 10. The base 12 is formed without side walls to provide a maximum access to wire connecting terminals 21, each of which comprises a wire clamp 22, a screw 24, and terminal 26. The wire connecting terminals 21 are positioned in spaced compartments 28 along opposite sides of an insulating terminal block 30. The terminal block 30 is secured to the rear wall 16 by a rivet 32, as shown in FIG. 16. The terminals 26 are L-shaped and each has a portion 34 secured to threaded inserts, not shown, that are embedded in the material of the block 30 and a portion 36 extending forwardly of the front side edges of the block 30.

The cover 14 is preferably formed of a molded insulating material and, in the embodiment shown in FIG. 1, includes a pair of openings 38 and 40 extending between a front wall 44 and a rear wall 46. The openings 38 and 40 are square-shaped and are located on centers that are spaced a preselected distance apart, which, in the embodiment shown in FIG. 1, is equal to 1.320 inches and herein designated as Y inches. The cover 14 is secured to the base 12 by a pair of screws 48 which are threaded into openings in ears 50 extending from the forward edges of the end walls 18. The cover 14 also includes side walls 52 extending rearwardly of the front wall 44 to close the open sides of the base 12 and ends 54 which receive the end walls 18.

A switch assembly 56 according to the present invention includes a housing 58 and the various components as will be hereinafter described as may be used with the housing 58.

The housing 58 is formed of a molded insulating material and, as shown in FIGS. 4 and 5, has an internal cavity 60. The cavity 60 has an open side 62 facing and positioned adjacent the rear wall 46 of the cover 14 and a rear wall 64 extending in a plane parallel and spaced from the rear wall 46. The cavity 60 is centered about a transverse plane 66. The plane 66 extends perpendicular to the rear wall 64 and is equidistantly spaced between the centers of the openings 38 and 40. The cavity 60 is also centered about a longitudinal plane 68. The plane 68 extends perpendicular to the rear wall 64 and passes through the centers of the openings 38 and 40. The housing 58 has an upper wall 70 and a lower wall 72 extending perpendicular to the rear wall 64 and parallel and equidistantly spaced at opposite sides of the plane 66 and parallel side walls 74 and 76 extending perpendicular to the rear wall 64 and equidistantly spaced at opposite sides of the plane 68. A pair of bores 78 and 80 are located at the upper and lower ends of the housing 58. The bores are centered in the plane 68 and are equidistantly spaced at opposite sides of the plane 66. Projecting forwardly from the rear wall 64 adjacent the respective side walls 74 and 76 are projections 82 and 84 which are centered in the plane 66 and spaced equidistantly at opposite sides of the plane 68. The projections 82 and 84 have bores 86 and 88 extending from a front surface of the respective projections 82 and 84 to an external rear surface side of the housing 58. The bores 86 and 88 are centered in the projections 82 and 84 and receive suitable screws, not shown, which are threaded in internal surface portions of the cover 14 to secure the housing 58 on the rear wall 46. The projections 82 and 84 respectively have grooves 90 and 92 centered in the plane 66 and extending parallel to the rear wall 64. The grooves 90 and 92 are spaced equidistantly at opposite sides of the plane 68.

Projecting forwardly from the rear wall 64 adjacent the respective side walls 74 and 76 are a pair of projections 94 and 96. The projections 94 and 96 extend perpendicular to the rear wall 46 and are centered in a plane 98 that extends parallel to the plane 66 at the upper half of the cavity 60. Similarly projecting forwardly from the rear wall 64 adjacent the respective side walls of the lower half of the cavity are a pair of projections 100 and 102. The projections 100 and 102 extend perpendicular to the rear wall 46 and are centered in a plane 104 that extends parallel to the plane 66. The planes 98 and 104 are parallel to each other and are equidistantly spaced a predetermined distance at opposite sides of the plane 66, as will be hereinafter described.

Each of the projections 94 and 96 has an individual groove 106 therein which faces the axis 68 and is centered in the plane 98. The grooves 106 extend perpendicular to the rear wall 64 and extend from the rear wall 64 to a front end on the respective projections 94 and 96. Similarly, each of the projections 100 and 102 has an individual groove 108 therein which faces the 104 and extend from the rear wall 64 to a front end on the respective projections 100 and 102. Extending forwardly from the rear wall 64 are a pair of bosses 109 which provide a pair of grooves 110 and 112. The groove 110 extends and is centered in the plane 98 and the groove 112 extends and is centered in the plane 104. A pair of stationary contact supports are associated with each of the projections 94, 96, 100 and 102 with the pair of supports associated with the respective projections designated by the numerical designation of its associated projection and suffixes a and b, as illustrated in FIGS. 4 and 5. The supports 94a and 94b are respectively located adjacent the up and lower sides of the projection 94 and are provided by projections extending forwardly from the rear wall 64 to a front surface 114 and are spaced from the side wall 74 to provide a passage 116 between each support 94a and 94b and the side wall 74. The passages 116 extend through the rear wall '64. Each of the supports has a bore 118 extending from the front surface 114 which receives a self-tapping screw l20, in a manner illustrated in FIG.

The pair of supports 100a and ,100b are respectively located at the upper and lower sides of the projection 100 in spaced relation to the side wall 74. Similarly, the supports 96d and 102a are located adjacent the upper side of the projections 96 and 102 respectively adjacent the side wall 76 and the supports 96b and l02b are located adjacent the lower side of the projections 96 and 102 respectively. The supports 94a-b, 96a-b, l00a-b, and 102a-b are identical and each has a front surface 114, a bore 118 and an associated passage 116 which correspond to the description of like elements of the supports 94a and 94b with the front surfaces 1 14 on all the supports extending in a common plane that extends parallel to the rear wall 64 and is spaced rearwardly of the front edges of the side walls 74 and 76.

Either of two types of stationary contacts may be secured on the supports 94a-b, 96a-b, l00a-b, and 102a-b in the manner illustrated in FIG. 8, wherein one type of stationary contact 122 is secured on the support 94b and a second type of stationary contact 124 is secured on the support 96b. However, each pair of adjaplane 68. The grooves 108 are centered in the plane cent supports are required to have the same type of stationary contacts 122 or 124 secured thereon.

Both types of stationary contacts 122 and 124 have a portion 126 secured on the surface 114 by the screw which passes through an opening in the portion 126 and is threaded into the bore 118 and a portion 128 which extends rearwardly through the passage 116 to a curved terminal portion 130 that extends rearwardly of the rear exterior of the rear wall 64. The terminal portions 130 are located to tightly engage a surface portiori on the portions 36 on the wire connecting terminals which are carried by the terminal block 30 when the cover 14 is secured to the base 12.

The stationary contacts 122 have portions 132 carrying stationary contact tips 134 extending in a common plane with portions 126. The tips 134, which are preferably formed of a noble metal, are secured on the portions 132 so the tips 134 face rearwardly in the cavity 60. The stationary contacts 124 have a portion 136 extending rearwardly along a side of the projections on which they are mounted to a portion 138 which has a contact tip 140 secured thereon. The portion 138 extends normal to the portion 136 and supports the tip 140, which is formed of a noble metal, so the tip 140 is positioned adjacent the rear wall 64 and faces forwardly in the cavity 60. As shown in FIGS. 4 and 5, the housing 58 also includes a ridge 142 formed on the rear wall 64 having its line of intersection extending in the plane 66.

A flush-mounted type control station 144, shown in FIGS. 6 and 7, includes a standard outlet box 146 as may be mounted in a wall of a building, a mounting bracket 148, and a cover 150. The outlet box 146 and the cover 150 are standard items of commerce and have fixed dimensions. The cover 150 includes a pair of circular openings 152 and 154 which are spaced 1.000 inches apart, and sized to receive a inch diameter cylindrical button. The 1.000 inch dimension is herein designated as x inches.

The outlet box 146 has a standard depth and is provided with knock-outs in its top and bottom walls 156, to side walls 157, its rear wall 158 and outwardly extending ears 159 at the front ends of the walls 156 which have threaded openings to receive screws 160 which secure the mounting bracket 148 within the interior of the box 146. The distance between the openings receiving the screws 160 is also fixed by standards. The mounting bracket 148, which permits the switch assembly 56 to be used in the flush-mounted control station 144, is Ushaped and has a rear wall 162, a pair of arms 164 extending forwardly from the rear wall 162, apertured ears 166-extending outwardly at the front ends of the arms 164 and apertured ears 168 extending inwardly from the arms 164. The apertures in the ears 166 are spaced to receive the screws 160. The cars 168 are spaced rearwardly a slight distance from the front ends of the arms 164 and have threaded openings to receive screws 170 which pass through the bores 78 and 80 to secure the switch assembly 56 to the bracket 148 and the cover 150 to the switch assembly 56. The openings receiving the screws 170 are also spaced a standard distance apart and when the cover 150, the mounting bracket 148 and the switch assembly 56 are assembled, as shown in FIG. 7, the open side 62 of the cavity 60 will be adjacent a rear wall side 172 of the cover 150.

As shown in FIGS. 7 and 8, the rear wall 162 has a rectangular opening 174 therein. Positioned on opposite sides of the opening 174 are terminal blocks 176 which are secured to portions of the rear wall 162 by screws 178. In the embodiment shown, four terminal blocks 176 are positioned at the sides of the opening 174 with two blocks positioned adjacent each longitudinal side of the opening 174. Each of the blocks 176 provides a support for a pair of wire connecting terminals 180 which are identical to the wire connecting terminals 21 previously described. The terminals 180 are positioned on the blocks 176 so the wire clamp portions 22 face the opening 174 to permit conduit wires to be passed from the rear portions of the outlet box 146 through the opening 174 where they may be readily secured when a bared end of the wire conduit is inserted between clamp 22 and the portion 34 and the screw 24 is tightened.

The housings 58, used in the switch assemblies in the control stations and 144, are identical. As previously described, the openings 38 and 40 in the cover 14 are located on centers spaced Y or 1.320 inches apart, and the openings 152 and 154 in the cover 150 are located on centers spaced X or 1.000 inches apart. The planes 98 and 104 are spaced (X+Y/2), or 1.160 inches apart, which permits the housing 58 to be used with either of the two covers 14 or 150.

A pair of movable contact carriers 182 and 183 may be positioned in the cavity 60. The contact carriers 182 and 183 are identical, with the contact carrier 182 positioned by the pair of grooves 106 for movement in the plane 98 and the contact carrier 183 positioned by the grooves 108 for movement in the plane 104. As the contact carriers 182 and 183 are identical, a description of the contact carrier 182 and its associated movable contacts will apply to the contact carrier 183 and its associated movable contacts. As shown in FIGS. 7 and 8, the contact carrier 182 is formed as a substantially flat stamped metal part and includes a portion 184 which has its outer side edges positioned within the grooves 106 and a portion 186 which extends forwardly from the portion 184 and the open side 62 of the cavity 60. The portion 184 has a central notch 188 and an opening 190 therein. The notch 188 and the opening 190 are centered in the plane 68. Disposed on opposite sides of the notch 188 are portions 192 and 194 which have rectangular openings 196 and 198 respectively located therein and spring seats located at the opposite ends of each of the openings 196 and 198. A movable contact assembly, including a movable contact 202 and a spring 204, may be positioned in either of two positions in each opening 196 and 198. Each movable contact 202 has a suitably notched central portion positioned within its associated opening 196 or 198 and arm portions 206 extending in opposite directions from the contact carrier 182 along an axis that is parallel to the plane 68. Each of the arm portions 206 has a noble metal contact tip 208 secured thereon which is located to engage the contact tips 134 when the movable contact 202 is in one of its two positions on the contact carrier 182 and the tips 140 when the movable contact 202 is at its other position on the carrier 182.

The movable contacts 202 in the openings 196 and 198 are arranged to engage and bridge a pair of stationary contacts 122 or 124 which are mounted on the adjacent pairs of projections 94a-b and 96a-b, respectively. For example, as shown in FIG. 8, a movable contact 202 is arranged to engage a pair of stationary contacts 124 which are mounted on the supports 96a and 96b, and a movable contact 202 is arranged to engage a pair of stationary contacts 122 that are mounted on the supports 94a and 94b. When the movable contact 202 is positioned in an opening 196 to engage the stationary contacts 122, the spring 204 associated therewith will be positioned between the movable contact 202 and the rear end of the opening 196. When the movable contact is positioned in the opening 198 to engage the stationary contacts 124, the spring 204 is positioned between the movable contact 202 and the front end of the opening 198. As shown in FIG. 8, when required, a spring 210 positioned within the notch 188 between the front end of the notch 188 and the rear wall 64, constantly urges the movable contact carrier 182 forwardly to a position wherein the movable contacts 202 engage the stationary contacts 122 to provide the switch assembly 56 with a normally closed type of contact function and to be disengaged from the stationary contacts 124 to provide a normally open type of contact function. The spring is positioned on the rear wall 64 by the boss 109.

A pair of buttons 212 having a square shape, as in FIG. 2, or a pair of buttons 214 having a cylindrical shape, as shown in FIG. 7, may be mounted on the portions 186 of the movable contact carriers 182 and 183. The buttons 212 are mounted on the portions 186 when the switch assembly 56 is mounted in a surface mounted control station 10 and the buttons 214 are mounted on the portions 186 when the switch assembly is mounted in a flush mounted type control station 144. The buttons 212, which are mounted on the contact carriers 182 and 183, are identical and therefore only the button 212 which is mounted on the carrier 183 will be described. As shown in FIGS. 1517, the button 212 has a square shaped front end 216 which is received in one of the square shaped openings 38 or 40 and a portion 218 which extends rearwardly from the front end 216. The portion 218 includes a forwardly extending recess which receives the portion 186 on the movable contact carrier 183. The recess in the portion 218 extends forwardly in the portion 218 in a plane that is displaced (Y-X/4) inches from a plane perpendicular to the front and through the center of the front end 216. The button 212 also has a rim portion 220 which surrounds at least a portion of the rear end of the front portion 216. The rim portion 220 is provided to engage the rear wall 46 to limit the forward movement of the button 212 in the opening 38. The buttons 212, when installed on the contact carriers 182 and 183 will have the centers of their respective front end portions 216 displaced a greater distance from the plane 66 than the planes 98 and 104 are respectively displaced from the plane 66 which will permit the switch assembly 56, including a pair of buttons 212 which are mounted on the carriers 182 and 183, to be combined with the cover 14.

The buttons 214 which are mounted on the carriers 182 and 183 are identical, and therefore only the button which is mounted on the carrier 182 will be described.

The button 214, as shown in FIGS. 9-12, has a cylindrical front end 222 which is received in one of the circular openings 152 or 154 and a portion 224 which extends rearwardly from the cylindrical end 222. The portion 224 includes a forwardly extending recess 226.

The recess 226 receives the portion 186 on the movable contact carrier 182 and extends forwardly in the portion 224 along a plane that is displaced (YX/4) inches from the central axis of the cylindrical end 222. The button 214 is also provided with a cylindrical rim 228 which surrounds the rear end of the cylindrical end 222. The rim 228 is provided to engage a rear side of a mounting plate 524, shown in FIG. 31A as will be later described, to limit the forward movement of the buttons 214 in the openings 152. The pair of buttons 214, when respectively installed on the carriers 182 and 183, will have the centers of their respective cylindrical ends 222 displaced a lesser distance from the plane 66 than the planes 98 and 104 respectively are displaced from the plane 66 which will permit the switch assembly 56, including the buttons 214, to be combined with the cover 150.

As shown in FIGS. 15 and 17, each button 212 has a square shaped recess 230 extending rearwardly in the front surface of the front end 216 and passages 234 at the centers of each of the four sides of the square recess 230 which extend rearwardly through the front end 216 with a removable insert 236 positioned in the recess 230. The insert 236 has a square shaped body portion 238 which is positioned in the recess 230 and a pair of fingers 240 which are received in two of the passages 234 when the body portion 238 is installed in the recess. The body portion 238 has a front surface 242 substantially flush with the front surface of the front end 216. A suitable legend, e.g., START or STOP, may be placed on the front surface 242 to indicate the switching function of the button 212. The fingers 240 are receivable in either a pair of vertically aligned passages 234 or a pair of horizontally aligned passages 234 so that when the control station is mounted in either a vertical position or a horizontal position, the legend on the front surface 242 may be oriented to extend horizontally. The fingers have portions which are received rearwardly of a ledge 244 in each passage to prevent displacement of the insert 236 from the recess 230 after the insert 236 is installed in the recess 230. The insert 236 is formed of a relatively stiff material which is capable of being flexed and the body portion is provided with at least one notch 246 on one of its sides which will accept a screwdriver tip to permit the insert to be pried from its position within the recess 230 when a re-orientation of the position of the insert 236 within the recess 230 is required.

As shown in FIGS. 9-12, each button 214 has a circular recess 248 extending rearwardly in the front end 222 and a removable insert 250 positioned in the recess 24 8. The insert 250 has a substantially circular body portion 252 which is positioned in the recess and a pair of fingers 253 which are received in a passage 254 that extends rearwardly through the front end 222. The body portion 252 has a front surface 256 substantially flush with the front surface of the front end 222. A suitable legend, e.g., START Or STOP, may be placed on the front surface 256 to indicate the switching function of the button 214. The fingers 253 have ends which hook behind ledges 258 in the passage 254 to maintain the insert 250 against displacement from the recess 248. The insert 250 is formed of a relatively stiff material which is capable of being flexed. A linear portion 260 is provided on the periphery of the substantially circular body portion 252 to provide a space wherein a screwdriver tip may be inserted to permit the insert 250 to be pried from its position within the recess 248 when replacement of the insert 250 is required.

When required, the switch assembly 56 may be provided with a lever 262 which will interlock the pair of movable contact carriers 182 and 183 and cause the switch assembly 56 to operate in either a maintained contact or a momentary contact closing mode of operation. The lever 262, as shown in FIGS. 13 and 14, is T- shaped, and has a leg portion 264 extending rearwardly in the cavity 60 and a pair of arm portions 266 and 268 extending in opposite directions along the axis 68 from the front end of the leg portion 264. A free end 270 on the arm 266 is received in the opening 190 in the carrier 182 and a free end 272 on the arm 268 is received in the opening 190 in the carrier 183. The front end of the leg portion 264 has a groove 274 therein and, as shown in FIG. 16, a bore 276 extending forwardly in the leg portion 264 from the rear end 278 of the leg portion 264.

When the lever 262 and the pair of springs 210 are included in the switch assembly, as shown in FIG. 13, the switch assembly 56 will function as an interlocked momentary contact closing switch. The springs 210 constantly urge the contact carriers 182 and 183 forwardly in the cavity 60 to a deactuated position wherein the contact tips 208 are separated from the contact tips 140. The lever 262 will be in effect floating in the cavity 60 with the free ends 270 and 272 sup ported in the openings 190 in respective contact carriers 182 and 183.

Either of the contact carriers 182 and 183 may be moved rearwardly in the cavity 60 to an actuated position when a manual force, which is applied to their associated buttons 212, overcomes the bias of the spring 210 on its associated carrier. The rearward movement of the contact carriers 182 and 183 is limited when the rear edges of the portions 192 and 194 engage the rear wall 64. A movement of one of the carriers 182 or 183, i.e., carriers 182, to its actuated position will cause the contact tips 208 to tightly engage the contact tips as the movable contact 202 moves in its associated opening 196 or 198 against the bias provided by its associated spring 204. The engagement between the tips 208 and 140 will complete a circuit between the sta tionary contacts 124 that are mounted on the pair of supports 94a and 94b. The movement of the carrier 184-will cause the free end 270 to move rearwardly and the lever 262 to rotate in a clockwise direction in FIG. 13 as the free end 272 remains stationary. The clockwise movement of the lever 262 causes the rear end 278 to engage the rear wall 64 and prevents the carrier 183 from being moved rearwardly to its actuated position in the cavity 60 during periods when the carrier 182 is at its actuated position. The release of the manual force on the carrier 182 will permit the spring 210 associated with the carrier 182 to move the carrier 182 forwardly to its deactuated position in the cavity 60 where the rims 220 on the button 212 or the rim 228 on the button 214 engage the rear wall of the covers 14 or the rear surface of the plate 524, respectively. The forward movement of the carrier 182 causes the tips 208 to move out of engagement with the tips 140 and the lever 262 to rotate in a counterclockwise direction to the position which will permit the contact carrier 183 to be moved rearwardly to its actuated position in the cavity 60.

The movement of the carrier 183 rearwardly in the cavity to its actuated position will cause the contact tips 208 to tightly engage the contact tips 140 as the movable contact 202 moves in its associated opening 196 or 198 against the bias provided by its associated spring 204. The engagement between the tips 208 and 140 will complete a circuit between the stationary contacts 124 that are mounted on the pair of supports 100a and 10012. The movement of the carrier 183 to its actuated position will cause the free end 272 to move rearwardly and the lever 262 to rotate in a counterclockwise direction in FIG. 13 as the free end 270 remains stationary. The counterclockwise movement of the lever 262 causes the rear end 278 to engage the rear wall 64 and prevents the carrier 182 from moving rearwardly to its actuated position in the cavity 60 during periods when the carrier 183 is at its actuated position. The release of the manual force on the carrier 183 .will permit the spring 210 associated with the carrier 183 to move the carrier 183 forwardly in the cavity 60 to its deactuated position where the rims 220 or 228 engage the rear wall of the covers 14 or the plate 524, respectively. The forward movement of the carrier 183 causes the tips 208 to move out of engagement with the tips 140 and the lever 262 to rotate in a clockwise direction to the position which will permit the contact carrier 182 to be moved to its actuated position in the cavity 60.

The switch assembly shown in FIG. 16 will provide a maintained contact mode of operation. The springs 210 are omitted from the assembly in FIG. 16 and a spring 280 and a ball 282 are positioned in the bore 276. The spring 280 constantly urges the ball 282 against the rear wall 64 and biases the lever 262 forwardly in the cavity. The lever 262 is pivoted on a pin 284. The pin 284 is received in the grooves 274, 90 and 92 and is held captive in the grooves 90 and 92 by screws 286 which are threaded into the bores 288.

The interl cking lever arrangement including the lever 262, the pin 284 and the ball 282 and the spring 280 will cause the carriers 182 and 183 to remain in their latest operated condition and prevent the carriers 182 and 183 from being simultaneously moved to their actuated positions. A movement of either of the carriers 182 and 183 rearwardly to its actuated position by a manual force which is applied their associated but-' tons 212 or 214 will cause the lever 262 to rotate in the cavity 60. When the carrier 183 is moved to its actuated position, the lever 262 will be rotated counterclockwise about the pin 284 to a position where the ball 282, which is biased by the spring 280, is positioned against a sloping portion 290 of the ridge 142, as shown in FIG. 5. The engagement between the ball 282 and the portion 290 will maintain the lever 262 in its counterclockwise position of rotation so that the carrier 183 is maintained in its activated position after the manual force on its associated button 212 or 214 is removed. The lever 262 will rotate in a clockwise direction when the carrier 182 is moved to its actuated position by a manual force which is applied to its associated button 212 or 214. The lever 262 will rotate about the pin 284 and during the clockwise rotation of the lever 262, the spring 280 will be compressed as the ball 282 passes over the apex of the ridge 142 and engages a sloping portion 292 of the ridge 142. The engagement between the ball 282 and the portion 292 causes the lever 262 to remain in its clockwise position of rotation after the manual force which caused the carrier 182 to move to its actuated position is removed. The spring 280 and the ball 282 act as a detent mechanism and cause the lever 262 to move with a snap action as the ball 282 moves over the apex of the ridge 142 during the rotation of the lever 262. The lever 262, when pivoted on the pin 284 and provided with the spring biased ball 282, will cause one of the contact carriers 182 or 183, i.e., carrier 183, to be maintained in its actuated position and the other carrier 182 to be in its de-actuated position while preventing both carriers 182 and 183 from being simultaneously moved to their actuated positions.

The housing 58 may be used with a rotary selector switch in either a surface mounted control station 10 or a flush mounted type control station 144. The flush mounted control station 144, as shown in FIG. 24, includes the housing 58 which positions a rotary selector switch mechanism 294 and a pilot lamp assembly 296 relative to the cover 150. The selector switch mechanism 294, as shown in FIG. 25, includes a rotatable contact carrier 298, an indexing plate 300, a guide plate 301, an indexing operator 302 for the carrier 298, and an operating knob 304.

Contact carrier 298 includes a body portion 306 and a portion 308 carrying gear teeth 310. The carrier has a center of rotation, when mounted in the cavity 60, located as a center 312 of an opening 314 in the portion 306. The body portion 306 has a thickness less than the width of the grooves 106, 108, and 112. A contact carrier 298 may be mounted in the pair of grooves 106 and the groove 110 or in the pair of grooves- 108 and the groove 112. In FIG. 24, the carrier 298 is shown as mounted in the pair of grooves 108 and the groove 1 12, it being understood that if desired a carrier 298 may be also mounted in the pair of grooves 106 and the groove 110. The body portion 306 has an arcuate rear edge 316 received in the groove 112 and arcuate opposite side edges 318 received in the pair of grooves 108. The arcuate edges 316 and 318 are formed as arcs of circles having their centers located at the center 312. The body portion 306 has a pair of openings 320 and 322.

As shown in FIG. 25, when the carrier 298 is at a centered position with the center of the portion 308 centered in the plane 68, the openings 320 and 322 will be located and spaced equidistantly on opposite sides of the plane 68. The openings 320 and 322 are substantially rectangular and have rear ends which extend along radii through the center 312 and are inclined so that the openings 320 and 322 will be substantially perpendicular to the rear wall 64 when the carrier 298 is respectively rotated counterclockwise and clockwise to its actuated positions in FIG. 25. Each of the openings 320 and322 has a movable contact 202 and a spring 204 positioned therein. The movable contacts 202 are positioned so their contact tips 208 face rearwardly and will engage the contact tips on a stationary contact 124 and thereby bridge two adjacent stationary contacts 124 when the carrier 298 is rotated to a proper position within the cavity 60.

As most clearly seen in FIG. 24, the portion 308 extends forwardly of the body portion 306 and extends in a plane that is parallel and spaced a predetermined distance from the plane in which the body portion 306 extends. In the embodiment shown, the distance between the planes of the body portion 306 and the portion 308 equals 0.12 inches. The gear teeth 310 face forwardly and have a root and tip diameter defined by radii through the center 312.

The indexing plates 300, shown in FIGS. 21C and 21B, are respectively mounted on the front end of the housing 58 when a selector switch version of the switch assembly 56 respectively is used in a surface mounted control station 10 and in a flush mounted control station 144. The plates 300 are formed of a relatively thin and rigid sheet of insulating material to have a pair of openings 330 which are aligned with bores 332 in the housing, see FIG. 4. The openings 330 and bores 332 are provided to receive screws 334 to secure the plates 300 on the front end of the housing 58, as shown in FIG. 25. As shown in FIG. 4, a pair of bores 332 are centered in the plane 98 and a pair of bores 332 are centered in the plane 104. The plates 300 in FIGS. 21B and 21C have an edge 336 which is positioned along the plane 66 when the plates 300 are mounted on the housing 58. The plates 300 have an opening 338 which receives a portion of the operator 302. The opening 338 in the plate 300, shown in FIG. 21C, is located on a center 0.08 inches from an axis passing through the centers of the pair of openings 330 and is located on the side of the axis that is remote from the edge 336. Similarly, the opening 338 in the plate 300 in FIG. 21B is located on a center 0.08 inches from the axis passing through the centers of the pair of openings 330 and is located on the edge 336 side of axis.

The plates 330 in FIGS. 21B and 21C each have five detent openings therein which are equidistantly spaced from the center of the opening 338, with one of the openings 340 centered about the plane 68. The opening 340 in the plate 300, shown in FIG. 21B, is located on the side of the axis through the centers of the pair of openings 330 that is remote from the edge 336. The opening 340 in the plate 300, shown in FIG. 21C, is located between the axis through the centers of the pair of openings 330 and the edge 336. Each plate 300 has two openings 342 located on centers that are displaced 60 clockwise and counterclockwise respectively from the center of the opening 340 and two openings 344 I- cated on centers that are displaced 120 degrees clockwise and counterclockwise from the center of the opening 340, so that each plate has the opening 340 and the pair of openings 342 located on one side of the axis through the centers of the openings 330 and a pair of openings 344 on the other side of the axis through the centers of the openings 330. The opposite ends of the edge 336 are notched to provide clearance for the bores 86 and 88 when the plates 300 are mounted on the front side of the housing 58.,

The guide plate 301, shown in FIGS. 32-35, is formed as a molded part and may be positioned in either of two positions within the cavity 60 which will permit the guide plate to be used in a surface mounted control station or in a flush mounted control station 144. The guide plate 301 has a rear surface 346 with a pair of projections 348 extending rearwardly from the rear surface 346. Each of the projections 348 has an outwardly projecting rib 350. The pair of ribs 350 provided by the pair of projections are received in the forward portions of the pair of grooves 106 and 108, while portions of the rear surface 346 rest upon the front surface portions 352 of the projections wherein the grooves 106 and 108 are located. Each of the projections 348 also has an inwardly extending groove 354 which is arcuate in shape and centered in the planes 98 and circumferentially spaced 90 degrees from the.

or 104 when the guide plate 301 is installed in portions of the cavity associated with the pair of grooves 106 and the pair of grooves 108, respectively. As the guide plates 301 may be installed in either pair of grooves 106 or 108, only the position of the guide plate in grooves 108 will be described, it being understood that the position of the guide plate is reversed from that described when the guide plate is installed in the grooves 106. The guide plate 301 has a circular opening 356 extending therethrough which is centered 0.08 inches from the plane 104 and a rectangular opening 358 therethrough. The opening 358 has a straight side 360 located to guide the portion 306 on the contact carrier 298 and a straight side 362 located to guide the portion 308 of the contact carrier 298. An arcuate rib 364 extending from the rear surface 346 has an edge aligned with the side 362 also provides a guide for the side edge on the portion 308. A front surface 366 on the guide plate 301 has an arcuate recess 368 therein which has a curvature defined by a radius centered in the center of the opening 356, and which terminates in a pair of stops 370 at the opposite sides of the recess 368. The recess 368 also has a pair of arcuate notches 372 which extend from the straight side 360. The notches 372 provide clearance for gear teeth 374 on a portion of the operator 302 as will now be described.

The operator 302, as most clearly seen in FIGS. 22 and 26-28, includes an operating member 376, a member 378 which causes the selector switch to have indexed positions, a spring 380, a ball 382, and a means including a member 384 and a bushing 386 which will releasablymaintain the members 376 and 378 in either of two relative positions so the switch assembly 294 will act as a two or a three position selector switch. The operating member 376 is formed as a molded insulating part to have a cylindrical stem 388 received in the opening 338 in a selected one of the two indexing plates 300 and a plate-like portion 390 at the rear end of the stern 388. The portion 390 is generally circular and has a flat front surface 392 engaging a rear surface on the selected indexing plate 300 with an extension extending from the periphery of the circular portion providing a pair of stops 394 on the periphery of the portion 390. Extending rearwardly from the rear surface of the portion 390 is a cylindrical projection 396 and the gear teeth 374. The projection 396 and the stem 388 are axially aligned and the gear teeth are rack-like and are centered between the stops 394 about a radius extending from the axis of the projection 396 which in the embodiment shown equals .21 inches.

Extending rearwardly from the forward end 398 of the stem 388 and axially aligned with the stem 388 is a circular recess 400 and a bore 402 with a pair of notches 404 extending rearwardly in the front end 398 along a planeequidistant between the stops 394 and defined by the axis of the stem 388 and a pair of notches 406 extending rearwardly in the front end 398 notches 404.

The indexing member 378 is substantially cylindrical, having a front end 408, a rear end 410 and a cylindrical bore 412 extending therethrough. The bore 412 receives the stem 388 with a rotatable fit. Extending outwardly from a side wall of the member 378 are a pair of spaced projections which provide a socket 414 which receives the spring 380 and the ball 382 with the ball 382 positioned at the rear end of the member to be received in any one of the openings 340, 342, or 344 with a detent-like action. The front end 408 is provided with a pair of notches 416 which are centered in a plane passing through the axis of the member 378 and the center of the ball 382.

The member 384 has an annular body portion 418, a circular opening 420 in the body portion 418 and four arms extending from the periphery of the body portion. The arms are spaced 90 apart with two of the arms 422 extending in opposite directions having a greater length than the other two arms 424. The bushing 386 has a cylindrical body 426, a rim 428 on one end of the body 426 and a threaded bore 430 extending through the body.

As shown in FIG. 27, a selected indexing plate 300, the operating member 376 and the indexing member 378 are maintained as an assembly by the member 384 and the bushing 386. The operating member 376 has its plate-like portion 390 positioned against the rear surface of the selected plate 300 and its stem 388 extending through the opening 338. The stem portion 388 is received in the bore 412. The member 384 has its body portion 418 received in the recess 400 and is maintained against rotation in the recess 400 by the pair of arms 424 which are received in the notches 406. The member 384 is secured on the front end 398 by the bushing 386 which has its cylindrical body extending through the opening 420 and is received in the bore 402 with a press fit. When the parts are thus assembled, the arms 422 will be received in the notches 404 and the notches 416. The member 378 has an axial length that is shorter than the length of the portion of the stern 388 that projects forwardly of the plate 300. The ball 382 is maintained in engagement with portions of the front surface of the selected indexing plate 300 by the spring 380. The spring 380 constantly biases the member 378 forwardly on the stem 388. The member 378 is maintained against rotation in either of two positions on the stem 388 by the arms 422 which are received in the notches 404 and 416. When the member 378 is in one of its positions on the stem 388, the ball 382 will be positioned to be received in either of the three openings 340 and 342. When the member 378 is in its second position on the stem 388, the ball 382 will be positioned to be received by either of the pair of openings 344. The ball 382 and the spring 380, together with the openings in the selected plate 300, provide a detent mechanism which releasably positions the operating member 376 and the indexing member 378 on the selected indexing plate 300. In FIG. 22, the parts are oriented so the ball 380 may be moved to either of three indexing positions which are defined by the opening 340 and the pair of openings 342. The position of the indexing member 378 on the stem 388 is changed by manually forcing the indexing member 378 against the force of the spring 380 toward the selected plate 300 to a position where the arms 422 are positioned forwardly of the front end 408 so that the member 378 may be rotated 180 degrees on the stem 388 to a position whereat the arms 422 are again aligned with the notches 416. When the manual force is released, the arms 422 will be received in the notches 416 and the member 378 will be held against rotation on the stem 388 and the ball 382 will be positioned to be received in either of the pair of openings 344 to releasably maintain the member 376 in the other of its two indexing positions.

As shown in FIGS. 29 and 30, the operating knob 304 has a cylindrically shaped body portion 432, a finger grip portion 434 extending forwardly of the body portion, a cruxiform recess 436 extending forwardly in the rear end of the body portion 432 and a bore 438 extending through the finger grip portion 434 and the body portion 432. The recess 436 has a circular central portion 440 with four radially extending arms 442 which are spaced apart about the periphery of the central portion 440. The finger grip portion 434 has a lenticular shape with one of its ends 444 being pointed to indicate the rotative position of the knob relative to a legend plate 445 which may be mounted in the opening 40 in the cover 14. Any one of the four arms 442 are sized to receive a portion 446 which projects from the side at the front end of the member 378 to provide a non-rotatable connection between the knob 304 and the member 378 when the front end 408 of the member 378 is received in the recess 436. The knob 304 and the member 378 are secured together by a screw 447 which is received in the bore 438 and the threaded bore 430. The portion 446 may be received in any one of the arms 442. One of the arms, e.g., arm 442a, is centered along a plane that passes through the center of the pointed end 444. As will be later described, the legend plate 445 may be mounted in at least two positions in the opening 40 and may be provided with legends such as MAN OFF AUTO, when the switch assembly is to operate as a three position selector switch or RUN JOG, if the assembly is to provide a two position selector switch operation. The legends are arranged on the legend plate 445 so .that the end 444 points to the appropriate legend when the contacts of the switch are positioned to provide the indicated function. The 90 spacing between the arms 442 permits the knob 304 to be positioned on the indexing member 378 so the lenticular finger grip portion 434 extends vertically independently of the position of the indexing member. This arrangement permits the legends on the legend plate 445 and the pointed end 444 to be properly oriented when the control station 10 is mounted in a horizontal or a vertical position.

The legend plate 445, shown in FIGS. 36 and 37, is formed of a relatively stiff molded insulating material to have a square shaped body portion 448 that is larger than the size of the square openings 38 and 40. The body portion 448 has a circular opening 450 centered therein which is sized to receive the body portion 432 of the knob 304 with clearance. The aforementioned legends may be applied to the front surface of the body portion 448. Extending rearwardly from the rear surface of the body portion 448 at each of the four corners of a square which has substantially the same size as the square openings 38 and 40 is projection 452. The projections 452 are received in the openings 38 or 40 and each includes an outwardly extending dimple 454 which engages the rear wall 46 to maintain the position of the legend plate 445 on the front wall 44 of the cover 14.

When the switch assembly 56 is assembled to provide a rotary selector switch operation in a flush-mounted type control station 144, as shown in FIGS. 24 and 25, the movable contact 298 is positioned in the pair of grooves 108 and the groove 112 to have the portion 308 carrying the gear teeth 310 extending in a plane that is displaced a greater distance from the plane 66 than the plane 104. The guide plate 301 is then installed in the cavity 60 with the ribs 350 received in the grooves 108 and the center of the opening 356 located between the planes 66 and 104. The assembly, including an indexing plate 300 as shown in FIG. 21B, the operator member 376, the indexing member 378, a spring 380, a ball 382, a member 384 and a bushing 386, is then secured on the front side of the cavity 60 by the screws 334 as shown in FIG. 23. The switch assembly 56 is then combined with the outlet box 146, the mounting bracket 148 and the cover 150 with the indexing member 378 extending through the opening 154 in the cover 150. The indexing member 378 is then programmed so the ball 382 will be received in the opening 340 if a three position selector switch operation is desired, or in the pair of openings 342 if a two position selector switch operation is desired, as previously described. The knob 304 is then positioned on the member 378 so the pointed end 444 points upwardly. The knob 304 is secured to the member 378 when the screw 447 is tightened in the bore 430.

When the switch assembly 56 is assembled to provide a rotary selector switch operation in a standard duty type control station 10, as shown in FIGS. 19 and 20, the movable contact 298 is positioned in the pair of grooves 108 and the groove 112 to have the portion 308 carrying the gear teeth 310 extending in a plane that is displaced a lesser distance from the plane 66 than the plane 104. The guide plate 301 is then installed in the cavity 60 with the ribs 350 received in the grooves 108 with the center of the opening 356 located a greater distance from the plane 66 than the plane 104 is spaced from the plane 66. The assembly, including an indexing plate 300 as shown in FIG. 21C, the operator member 376, the indexing member 378, the spring 380, the ball 382, the member 384 and a bushing 386, is then secured on the front side of the cavity 60 by the screws 334. The legend plate 445 is then inserted into the opening 40 and the switch assembly is then combined with the cover 14 with the indexing member 378 extending through the opening 450 in the legend plate 445. The indexing member 378 is then programmed so the ball 382 will be received in the opening 340 if a three position selector switch operation is desired, or in the pair of openings 342 if a two position selector switch operation is desired, as previously described. The knob 304 is then positioned on the member 378 so the pointed end 444 points upwardly. The knob 304 is secured to the member 378 when the screw 447 is tightened in the bore 430.

As previously described, the planes 98 and 104 are spaced 1.160 inches apart, the openings 38 and 40 are spaced 1.320 inches apart, and the openings 152 and 154 are spaced 1.000 inches apart. Thus the centers of the pair of grooves 108 and the groove 112 are displaced 0.58 inches from the plane 66 and the centers of the openings 40 and 154 are respectively displaced 0.66 and 0.5 inches from the plane 66. The center of the opening 356 in the guide plate 301 is displaced 0.08 inches from the centers of the ribs 350. Thus, when the guide plate 301 is installed in one of its two positions in the cavity 60, the center of the opening 356 will be displaced 0.50 inches from the plane 66 and be aligned with the center of the opening 154. When the guide plate 301 is installed in the other of its two positions in the cavity 60, the center of the opening 356 will be displaced 0.66 inches from the plane 66 and be aligned with the center of the opening 40.

The centers of the openings 338 in the indexing; plates 300, shown in FIGS. 21B and 21C, are also displaced 0.08 inches from a line of centers through the openings 330. The openings 330 are centered in the plane 104 when either of the plates 300 is mounted on the front side of the housing 58. Thus the centers of the openings 338 will be aligned with the openings 40 and 154 when the plates respectively shown in FIGS. 21C and 21B are mounted on the housing 58.

The gear teeth 310 are centered in a plane which is displaced 0.12 from the plane 104 when the body portion 306 is positioned in the pair of grooves 108 and the groove 112. Thus, when the movable contact carrier 298 is positioned in the pair of grooves 108 and the groove 112, as shown in FIG. 24, the plane in which the gear teeth 310 extend will be displaced 0.70 inches from the plane 66. When the carrier 298 is positioned in the air the pair of grooves 108 and the groove 112, as shown in FIG. 20, the plane in which the gear teeth 310 extend will be displaced 0.46 inches from the plane 66.

The arcuate gear teeth 374 are centered on radius of 0.21 inches from central axis of the projection 396. The projection 396 is received in the opening 356 in the guide plate 301. The operating member 302 when assembled in a flush mounted control station 144, as shown in FIG. 24, will be positioned so the gear teeth 374 are movable about a radius which is centered 0.50 inches from the plane 66. Thus the gear teeth 374 will be displaced 0.71 inches from the plane 66 and be located to mesh with the gear teeth 310 which are displaced O.70 inches from the plane 66 when the carrier 298, the indexing plate 300, the guide plate 301 and the operating member 302 are positioned by the housing 58, as shown in FIG. 24. The operating member 302 when positioned in a surface mounted control station 10, as shown in FIG. 20, will be positioned so the gear teeth are movable about a radius which is centered 0.66 inches from the plane 66. Thus the gear teeth 374 will be displaced 0.45 inches from the plane 66 and be located to mesh with the gear teeth 310 which are displaced 0.46 inches from the plane 66 when the carrier 298, the indexing plate 300, the guide plate 301 and the operating member 302 are positioned by the housing, as shown in FIG. 20.

The pair of indexing openings 342 in the indexing plates shown in FIGS. 21B and 21C are spaced apart and the pair of indexing openings 344 are spaced 120 apart. The stationary contacts 124 are used in the selector switch version of the switch assembly 56.

When the indexing member 378 is programmed to provide a three indexed position mode of operation and the knob 304 is positioned so the ball 382 is received in the opening 340, as in FIG. 25, the carrier 298 will be positioned so that both sets of contact tips 208 are separated from both pairs of stationary contact tips 140. When the knob 304 is rotated 60 in a clockwise direction, the carrier 298 will rotate counterclockwise and cause the tips 208 to engage the pair of stationary contacts on the left side of the housing 58 to complete a circuit therebetween. When the knob 304 is rotated 60 counterclockwise, the carrier 298 will rotate clockwise and cause the tips 208 to engage the pair of tips 140 on the right side of the housing to complete a circuit therebetween.

When the indexing member 378 is programmed to provide a two indexed position mode of operation, the

knob 304 and carrier 298 will be maintained in either of two extreme positions from which they may be rotated to alternately complete circuits between the pairs of contact tips 140 at the right and the left sides of the cavity 60. The knob 304 and the contact carrier 298 will be maintained at the two selected indexed positions by the indexing mechanism that includes the spring biased ball 382 and the respective openings 344 in the indexing plate 300.

A selector switch version of a surface mounted control station or a flush mounted control station 144 may be furnished with a pilot lamp assembly 460, as will now be described. The pilot light assembly 460, as shown in FIGS. 23 and 24, includes a lamp socket 462, a lamp 464, three terminals 466, a pair of contact members 468 and 470, a resistor 472 and a selected mounting plate 474, as shown in FIGS. 31B and 31C.

The lamp socket 462, as shown in FIGS. 38, 38A and 39, is formed of a rigid molded insulating material to have a body portion 476, a pair of projections 478 extending in opposite directions from the body portion and a pair of spaced projections 480 extending rearwardly from the body portion 476. Each of the projections 478 has a rib 482 at its free end which is received in one of the grooves 106 while portions of the free ends of the projections 478 on opposite sides of the ribs 482 rest upon the surfaces 352 on the front ends of the projections 94 and 96. The body portion 476 has a circular recess 484 having a diameter sufficient to receive a commercially available lens 486 when the pilot light assembly 460 is used in a flush mounted control station 144. The center of the recess 484 is displaced 0.08 inches from an axis extending through the center of the ribs 482. The rear wall of the body portion 476 has an opening 488 and the projections 480 extend rearwardly from opposite sides of the opening 488 and are centered in the plane 68 when the socket 462 is positioned in the cavity 60. The opposite walls of the recess 484 are provided with ribs 490 which receive threads on the lens 486 to position the threaded end of the lens 486 in the recess 484.

The mounting plates 474, shown in FIGS. 31C and 31B, are mounted on the front end of the housing 58 7 when a pilot light assembly 460 is respectively included in a surface mounted control station 10 and a flush mounted control station 144. The plates 474 are formed of a relatively thin and rigid sheet of insulating material to have a pair of openings 492 which are aligned with the bores 332. The openings 492 and the bores 332 receive the screws 334 to secure the plates 474 on the front end of the housing 58. The plates 474 in FIGS. 31B and 31C have an edge 494 which is positioned in the plane 66 when the plates 474 are mounted on the housing 58. Each of the plates 474 has an opening 496 which receives the body portion 476. The opening 496 in the plate shown in FIG. 31C is located 0.08 inches from an axis passing through the centers of the pair of openings 492 and is located on the side of 498 and is threaded into the bore 118 and a portion which extends rearwardly through the passage 116 to a curved terminal portion 500 that extends rearwardly of the rear exterior of the rear wall 64. The terminal portions 500 are located to tightly engage a surface portion on the portions 36 on the wire connecting terminals which are carried by the terminal block 30 in the standard duty control station 10, or the terminals carried by the terminal block 176 in the flush-mounted control station 144. As shown in FIG. 23, a contact member 468 and 470 iS secured to the portions 498 of the terminal members 466 that respectively rest on the projections 94b and 96b of the housing 58. The member 468 has a contact portion 502 extending upwardly in the cavity to be received between the projections 480 on the socket 462 when the socket is installed in cavity 60 for use in a control station 144. Similarly, the member 470 has a contact portion 504 extending upwardly in the cavity 60 to be received between the projections 480 when the socket 462 is positioned to be used in a control station 144. The resistor 472 is connected between the portions 498 of the terminal members 466 which are mounted on the projections 96a and 9612. When the terminal members 466 are mounted as shown, the contact portions 502 and 504 will be spaced on opposite sides of the plane 68 and be centered along an axis that is spaced between the planes 66 and 98.

When the pilot lamp assembly 460 is to be used in a control station 10, the terminal member 466 carrying the contact member 468 is secured on the projection 96a and the terminal member 466 carrying the contact member 470 is secured on the projection 94a so that the contact portions 502 and 504 extend downwardly in the cavity and are spaced on opposite sides of the plane 68 and are centered along an axis that is spaced between the plane 98 and the top wall 70. The resistor 472 will be connected between the terminal members 466 that are respectively mounted on the projections 96a and 96b. When the terminals 466 are mounted in the cavity 60 for use in a control station 10, the contact portions 502 and 504 will be received between the projections 480 when the socket 462 is positioned to be used in a control station 10 and a mounting plate 474, as shown in FIG. 31C, is secured to the front side of the housing 58.

The lamp 464 is a commercially available type having a sealed tubular glass envelope 506 with a filament 508 at a front end of the envelope 506, a pair of terminals 510 extending along the opposite surface sides of the envelope 506 from a rear end of the envelope 506 and an insulating pointed tip 512 at the rear end of the envelope 506. The ends of the filament 508 are respectively connected to the pair of terminals 510.

The control station 10 also includes a lens 514, shown in FIG. 20, which is formed of a light transmitting plastic to have a square shape which will permit a portion 516 to be received in the opening 38 while the perimeter of a front end portion 518 engages portions of the front wall 44. The portion 516 preferably includes a pair of nibs 520 which snap behind portions of two opposite sides of the opening 38 to maintain the lens 514 in the opening 38.

The switch assembly 56 is assembled to provide a pilot light in a control station 144 by mounting the three terminal members 466, the two contact members 468 and 470, and the resistor 472 in the cavity 60, as shown in FIG. 23 and previously described. The socket 462 is then positioned in the cavity 60 with the ribs 482 received in the grooves 106 and portions on the projections 478 resting on the surfaces 352. The socket 462, when positioned in the cavity 60, will have the center of the recess 484 centered in the plane 68 and displaced 0.08 inches from the plane 98 in a direction which will cause the center of the recess 484 to be displaced 0.50 inches from the plane 66. The positioning of the socket 462 as described will cause the contact portions 502 and 504 to be positioned in the space between the projections 480. The mounting plate 474, as shown in FIG. 31B, when secured on the front side of the cavity 60 by screws 334 which pass through the openings 492 and into the bores 332, will be positioned so that the body portion 476 extends through the opening 496 and a rim 522 at the rear end of the body portion 476 engages rear surface portions on the mounting plate 474 to maintain the socket 462 within the cavity 60. The lamp 464, when inserted into the socket 462, will have its terminals 510 engaging the contact portions 502 and 504 and its pointed tip 512 engaging the boss 109. The switch assembly 56 is then combined with the outlet box 146, mounting bracket 148 and cover 150 with the center of the recess 484 aligned with the center of the opening 152 and the filament end of the lamp 464 extending through the opening152. The lens 486 is then positioned in the opening 484 when a threaded end on the lens engages the ribs 490.

The switch assembly 56 is assembled to provide a pilot light in a control station by mounting the terminal members 466 on the housing 58 so that the contact portions 502 and 504 extend downwardly, as previously described. The socket 462 is then positioned in the cavity 60 with the ribs 482 received in the grooves 106 and portions on the projections 478 resting on the surfaces 352. The socket 462, when positioned in the cavity 60, will have the center of the recess 484 centered in the plane 68 and displaced 0.08 inches from the plane 98 in a direction which will cause the center of the recess 484 to be displaced 0.66 inches from the plane 66. The positioning of the socket 462, as described, will cause the contact portions 502 and 504 to be positioned in the space between the projections 480. The mounting plate 474, as shown in FIG. 31C, when secured on the front side of the cavity 60 by screws 334 which pass through the openings 492 and into the bores 332, will be positioned to have the body portion 476 extending through the opening 496 and a rim 522 on the body portion 476 engaging rear surface portions on the mounting plate 474 to maintain the socket 462 within the cavity 60. The lamp 464, when inserted into the-socket 462, will have its terminals 510 engaging the contact portions 502 and 504 and its pointed tip 512 engaging the boss 109.

i The switch assembly 56, having the pilot light assembly 460 positioned therein, is then combined with the cover 14 which has a lens 514 previously installed in the opening 38 as previously described. When the switch assembly 56 is mounted on the rear wall 46, the filament end of the lamp 464 will extend through the opening 38, as shown in FIG. 20,- where it will be visible through the lens 514.

The lamp 464, as used in the pilot light assembly 460, preferably has a rating of 120 volts. Thus the pilot light may be connected in a 120 volt circuit when electrical connections are made directly to the terminals 466 on which the contact members 502 and 504 are mounted.

When the lamp is to be energized from a higher voltage source, a connection to the terminal 466 which will place the resistor 472 in series with the lamp is utilized.

The plates 522 and 524, respectively shown in FIGS. 21A and 31A, are mounted on the front end of the housing 58 when the switch assembly 56 is used in a control station 144. The plates 522 and 524 are formed of a relatively thin rigid sheet of insulating material to have a pair of openings 526 which are aligned with the bores 332. The openings 526 and the bores 332 receive the screws 334 to secure either of the plates 522 or 524 on the front end of the housing 58. The plates 522 and 524 have an edge 528 which is positioned in the plane 66 when the plates are mounted on the front surface of the housing 58. The plate 522 does not have a central opening therein and is used when the control station 144 is of the single unit type. For example: the control station 144 may be assembled to include a single selector switch, push button or pilot lamp which extends through one of the two openings in cover 150 with the remaining opening being unused. The plate 522 provides a cover for the portion of the cavity 60 located rearwardly of the unused opening. The plates 524 are used to provide a guide for the cylindrical buttons 214 and to maintain the components of the switch assembly 56 within the housing 58 prior to the installation of the cover 150 on the control station 144. The plate 524 has an opening 530 which receives the cylindrical button 214. The opening 530 in the plate shown in FIG. 31A is located 0.08 inches from the axis passing through the center of the pair of openings 526 and is located on the edge 528 side of the axis. The plates 524 are mounted in the control station 144, as shown in FIGS. 7 and 8.

The control stations 10 and 144, as previously described, are known as one or two unit type control stations as the maximum number of switching units or pilot lights that could be accommodated by the stations is two pilot lights, two selector switches, two push buttons or combinations thereof. However, three unit surface mounted control stations are frequently required to provide switching functions in an installation. For example, a control station may be required to have three buttons, i.e., an UP button, a DOWN button and a STOP button. A control station may be required to have a selector switch and two buttons or a control station may be required to have two buttons and a pilot light. A control station 532, as shown in FIGS. 15-18, will accommodate three units and is basically an elongated version of the control station 10 and therefore the numerical designations which are used to describe the structure of the control station 10, where appropriate, will be used to describe the structure of the control station 532.

The control station 532 includes a cover 534 and a base 536 which respectively replace the cover 14 and the base 12 as used in the control station 10. Also, for purposes of economy of manufacture, the control station 532 includes an additional housing 538, an insulating member 540, and an indexing plate 541, shown in FIG. 21D, or a mounting plate 543, shown in FIG. 31D, which are required when the control station 532 is assembled from the components previously described in connection with the control station 10. The cover 534, in addition to the openings 38 and 40, includes an additional opening 542 which has the same shape and size as the openings 38 and 40 and has its center located in the plane 66 and spaced 1.320 inches from the center of the opening 38. The base 536, in addition to providing a support for the insulating block 30, which sup ports the terminals 26 as previously described, includes a portion which provides a support for a pair of terminal blocks which are identical to the terminal blocks 176 which are used in the control station 144. The blocks 176 are mounted on a rear wall 544 of the base 536 with the insulating member 540 positioned between the blocks 176 and the metal rear wall 544. The blocks 176 have terminals 180 thereon which are oriented relative to the opening 542 in the control station 532 in the same manner as the terminals 26 are positioned relative to the openings 38 and 40 by the block 30.

The housing 538 is formed of a molded insulating material and, as shown in FIG. 40, includes an internal cavity 546. The cavity 546 is centered about the plane 68 and has an open side facing and positioned adjacent a rear wall 547 of the cover 534. The cavity 546 has a rear wall 548 extending coplanar with the rear wall 64 and is centered about a plane 550 which extends perpendicular to the rear wall 548 and extends parallel to and is spaced 1.320 inches from the plane 98 when the housing 538 is mounted adjacent the upper end of the housing 58. The housing 538 is provided with a pair of ears at its upper end, each of which has a bore 552. The bores 552 receive suitable screws 554 which are threaded into portions of the cover to secure the housing 538 on the rear wall 547 in a position where a lower wall 556 is positioned adjacent a top end of the housing 58 to maintain the 1.320 inch spacing between the planes 98 and 550. The housing 538 has a pair of side walls 558 and 560 coplanar with the respective side walls 74 and 76 and projections 562 and 564 extending perpendicular to the rear wall 548 and centered in the plane 550. The housing also has projections, bosses, grooves and openings which provide the equivalent function in the housing 538 as the pair of grooves 106, the groove 110, the openings 116, the supports 94a-b and 96a-b provide in the upper portion of the cavity 60. Thus the same components used in connection with the control station which were installed in the portion of the cavity 60 associated with the pair of grooves 106 and the groove 110 may be installed in the cavity 546 to provide a switch assembly which will permit a push button, a pilot light or a selector switch to be present in the opening 542 in the same manner as similar components were assembled to be present in the opening 38 in the control station 10. The indexing plate 541, shown in FIG. 21D, and the mounting plate 543, shown in FIG. 31D, are substantially identical to the indexing plate 300 and the mounting plate 474 which are respectively shown in FIGS. 21C and 31C. The only difference between the plates 541 and 543 and the plates 300 and 474 is that a bottom edge 572 on theplates 541 and 543 is spaced a lesser distance from an axis through the corresponding mounting holes 330 and 492 in the plates 541 and 543 respectively than the edges 336 and 494 are spaced from the axis through the mounting holes 330 and 492 in the plates 300 and 474, respectively.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In an electric switch assembly that is selectively usable with either of two switch covers with a first of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of said two covers having a pair of openings therein spaced equidis tantly on opposite sides of a center of the second covers on centers Y inches apart and wherein X is less than Y, said assembly including: a housing mounted adjacent a rear wall and rearwardly of the pair of openings in a selected one of the pair of covers, said housing having an internal cavity with said cavity having an open side facing the rear wall, a center located on an axis extending through the center of the cover and portions extending rearwardly of the openings in the cover, and a pair of movable contact carriers in said cavity spaced equidistantly on opposite sides of the center of the cavity and movable in parallel planes spaced (X+Y/2) inches apart in the portions of the cavity that extend rearwardly of the pair of openings in the cover.

2. The switch assembly as recited in claim 1 wherein the openings in the first cover are circular and the openings in the second cover have a square shape.

3. The switch assembly as recited in claim 1 including an operator having an actuating portion centered on an axis through the center of one of the openings in the cover and an operating portion disposed at the rear wall side of the cover and located (Y-X/4) inches from the axis providing a connection between the actuating portion and the movable contact carrier in the portion of the cavity that extends rearwardly of the said one opening.

4. The switch assembly as recited in claim 3 wherein the operator is a linearly movable push button.

5. The switch assembly as recited in claim 1 wherein the movable contact carrier that is movable in the cavity in one of the pair of openings is replaced by an assembly that includes a pilot light.

6. The switch assembly as recited in claim 1 wherein the portions of the cavity that extend rearwardly of the pair of openings have spaced stationary contacts therein which are engaged by contacts that are carried by the movable contact carrier.

7. An electricswitch assembly that is selectively usable with either of two covers with a first of said two covers having a pair of openings spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second cover on centers Y inches apart wherein X is less than Y, said switch assembly comprising: a selected one of the two covers, a housing mounted adjacent a rear wall of the selected cover, said housing having walls which provide a first contact chamber that extends rearwardly of a first of the two openings in the selected cover, a second contact chamber extending rearwardly of a second of the two openings in the selected cover, a pair of slots in each contact chamber centered in a plane perpendicular to the rear wall of the cover and an axis passing through the centers of the openings and located so the planes are (X+Y/2) inches apart and are spaced equidistantly from an axis extending perpendicular to the rear wall and through the center of the selected cover, a first movable contact support movable in the pair of slots in the first chamber, a second movable contact support movable in the pair of slots in the second chamber, a first push button having an actuating portion centered on an axis through the center of the first opening in the selected cover and an operating portion disposed at the rear wall side of the cover located (YX/4) inches from the axis of the actuating portion providing a connection between the actuating portion and the first contact support for moving the first contact support when the actuating portion of the first push button is moved in the first opening, a second push button having an actuating portion centered on an axis through the center of the second opening in the selected cover and an operating portion disposed at the rear wall side of the cover located (YX/4) inches from the axis of the actuating portion providing a connection between the actuating portion and the second contact support for moving the second contact support when the actuating portion of the second push button is moved in the second opening, and a lever having its opposite ends connected respectively to the first contact support and the second contact support and a midportion engageable with a projection on a rear wall of the housing providing a mechanical interlock between I the first and the second contact supports for preventing simultaneous actuation of the first and the second contact supports by the first and the second push buttons.

8. The switch assembly as recited in claim 7 including a first return spring positioned between the rear wall of the housing and the first contact support constantly biasesthe first contact support and the first push button to a deactuated position and a second return spring positioned between the rear wall of the housing and the second contact support constantly biases the second contact support and the second push button to a deactuated position.

9. The switch assembly as recited in claim 8 wherein the lever is pivoted on a portion of the housing and includes a detent mechanism carried by the mid-portion of the lever and engageable with the rear wall of the I housing.

10. The switch assembly as recited in claim 7 wherein the lever is pivoted on a portion of the housing and prevents simultaneous actuation of the first contact support and the second contact support from a deactuated position to an actuated position and includes a detent mechanism carried by the midportion of the lever and engageable with a portion of the rear wall of the housing for maintaining a selected one of the first and the second contact supports in its actuated position and the unselected contact support in its deactuated position.

11. An electric switch assembly comprising: a cover having a front side, a rear side and a pair of openings extending between the front and the rear sides, a molded housing mounted on the rear side, said housing having a pair of side walls and a rear wall extending between'the side walls providing the housing with a first open-sided chamber that extends rearwardly of a first of the pair of openings and a second open-sided chamber that extends rearwardly of a second of the pair of openings, a pair of slots in the side walls of the first chamber extending in a plane perpendicular to the side walls and parallel and spaced a predetermined distance from an axis perpendicular to the rear side through the center of the first opening, a movable contact support positioned by the slots in the first chamber for rotation about an axis perpendicular to the plane between two positions, a pair of stationary contacts positioned by one of the side walls in spaced relation on opposite sides of the plane in the first chamber adjacent the one side wall side of the first chamber, a movable contact carried by the contact support and engaging the pair of stationary contacts when the contact support is at a first of its two positions and spaced from the pair of stationary contacts when the contact support is at a second of its two positions, an actuator positioned at the open side of the first chamber, said actuator having an operating position extending through the first opening and rotatable about the axis centered in the first opening, an actuating portion including rearwardly facing gear teeth arranged in an arc having a radius centered on the axis through the center of the first opening engageable with gear teeth on the contact support for rotating the contact support to the two positions, and detent means yieldably maintaining the actuator in either of two selected positions, an adjustment knob posi tioned on the operating portion of the actuator on the front side of the cover, and a pilot light assembly positioned in the second chamber.

12. The switch assembly as recited in claim 11 wherein the pilot light assembly includes a pair of terminals respectively positioned by the side walls of the housing and positioned at opposite sides of an axis perpendicular to the rear side through the second opening, a receptacle for the pilot light positioned at the open side of the second chamber, a pilot light positioned in the receptacle to have terminal portions engaging the terminals within the chamber and a bulb portion extending through the second opening in the cover, and a lens providing a cover for the second opening in the cover.

13. An electric switch assembly that is selectively usable with either of two switch covers with a first of the two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of the two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second cover on centers Y inches apart and wherein X is less than Y, said assembly including: a selected one of the two covers, said selected cover having a front side and a rear side, a molded housing mounted adjacent the rear side, said housing having a pair of parallel side walls spaced equidistantly on opposite sides of an axis through the centers of the openings and a rear wall extending between the side walls providing the housing with a first open-sided chamber that extends rearwardly of a first of the pair of openings in the selected cover and a second open-sided chamber that extends rearwardly of a second of the pair of openings in the selected cover, a pair of slots in the side walls of the first chamber extending in a plane perpendicular to the side walls and parallel and spaced (X+Y/4) inches from an axis perpendicular to the rear side through the center of the selected cover, a pair of stationary contacts positioned by one of the side walls in spaced relation on opposite sides of the plane in the first chamber adjacent the said one side wall of the chamber, a movable contact assembly in the first chamber, said contact assembly including a movable support having a contact support portion positioned by the pair of slots in the first chamber for rotation about an axis perpendicular to the plane between two positions and an actuating portion spaced a predetermined distance and extending parallel to the plane, said actuating portiOn having gear teeth thereon 

1. In an electric switch assembly that is selectively usable with either of two switch covers with a first of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second covers on centers Y inches apart and wherein X is less than Y, said assembly including: a housing mounted adjacent a rear wall and rearwardly of the pair of openings in a selected one of the pair of covers, said housing having an internal cavity with said cavity having an open side facing the rear wall, a center located on an axis extending through the center of the cover and portions extending rearwardly of the openings in the cover, and a pair of movable contact carriers in said cavity spaced equidistantly on opposite sides of the center of the cavity and movable in parallel planes spaced (X+Y/2) inches apart in the portions of the cavity that extend rearwardly of the pair of openings in the cover.
 2. The switch assembly as recited in claim 1 wherein the openings in the first cover are circular and the openings in the second cover have a square shape.
 3. The switch assembly as recited in claim 1 including an operator having an actuating portion centered on an axis through the center of one of the openings in the cover and an operating portion disposed at the rear wall side of the cover and located (Y-X/4) inches from the axis providing a connection between the actuating portion and the movable contact carrier in the portion of the cavity that extends rearwardly of the said one opening.
 4. The switch assembly as recited in claim 3 wherein the operator is a linearly movable push button.
 5. The switch assembly as recited in claim 1 wherein the movable contact carrier that is movable in the cavity in one of the pair of openings is replaced by an assembly that includes a pilot light.
 6. The switch assembly as recited in claim 1 wherein the portions of the cavity that extend rearwardly of the pair of openings have spaced stationary contacts therein which are engaged by contacts thAt are carried by the movable contact carrier.
 7. An electric switch assembly that is selectively usable with either of two covers with a first of said two covers having a pair of openings spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second cover on centers Y inches apart wherein X is less than Y, said switch assembly comprising: a selected one of the two covers, a housing mounted adjacent a rear wall of the selected cover, said housing having walls which provide a first contact chamber that extends rearwardly of a first of the two openings in the selected cover, a second contact chamber extending rearwardly of a second of the two openings in the selected cover, a pair of slots in each contact chamber centered in a plane perpendicular to the rear wall of the cover and an axis passing through the centers of the openings and located so the planes are (X+Y/2) inches apart and are spaced equidistantly from an axis extending perpendicular to the rear wall and through the center of the selected cover, a first movable contact support movable in the pair of slots in the first chamber, a second movable contact support movable in the pair of slots in the second chamber, a first push button having an actuating portion centered on an axis through the center of the first opening in the selected cover and an operating portion disposed at the rear wall side of the cover located (Y-X/4) inches from the axis of the actuating portion providing a connection between the actuating portion and the first contact support for moving the first contact support when the actuating portion of the first push button is moved in the first opening, a second push button having an actuating portion centered on an axis through the center of the second opening in the selected cover and an operating portion disposed at the rear wall side of the cover located (Y-X/4) inches from the axis of the actuating portion providing a connection between the actuating portion and the second contact support for moving the second contact support when the actuating portion of the second push button is moved in the second opening, and a lever having its opposite ends connected respectively to the first contact support and the second contact support and a mid-portion engageable with a projection on a rear wall of the housing providing a mechanical interlock between the first and the second contact supports for preventing simultaneous actuation of the first and the second contact supports by the first and the second push buttons.
 8. The switch assembly as recited in claim 7 including a first return spring positioned between the rear wall of the housing and the first contact support constantly biases the first contact support and the first push button to a deactuated position and a second return spring positioned between the rear wall of the housing and the second contact support constantly biases the second contact support and the second push button to a deactuated position.
 9. The switch assembly as recited in claim 8 wherein the lever is pivoted on a portion of the housing and includes a detent mechanism carried by the mid-portion of the lever and engageable with the rear wall of the housing.
 10. The switch assembly as recited in claim 7 wherein the lever is pivoted on a portion of the housing and prevents simultaneous actuation of the first contact support and the second contact support from a deactuated position to an actuated position and includes a detent mechanism carried by the midportion of the lever and engageable with a portion of the rear wall of the housing for maintaining a selected one of the first and the second contact supports in its actuated position and the unselected contact support in its deactuated position.
 11. An electric switch assembly comprising: a cover having a front side, a rear sIde and a pair of openings extending between the front and the rear sides, a molded housing mounted on the rear side, said housing having a pair of side walls and a rear wall extending between the side walls providing the housing with a first open-sided chamber that extends rearwardly of a first of the pair of openings and a second open-sided chamber that extends rearwardly of a second of the pair of openings, a pair of slots in the side walls of the first chamber extending in a plane perpendicular to the side walls and parallel and spaced a predetermined distance from an axis perpendicular to the rear side through the center of the first opening, a movable contact support positioned by the slots in the first chamber for rotation about an axis perpendicular to the plane between two positions, a pair of stationary contacts positioned by one of the side walls in spaced relation on opposite sides of the plane in the first chamber adjacent the one side wall side of the first chamber, a movable contact carried by the contact support and engaging the pair of stationary contacts when the contact support is at a first of its two positions and spaced from the pair of stationary contacts when the contact support is at a second of its two positions, an actuator positioned at the open side of the first chamber, said actuator having an operating position extending through the first opening and rotatable about the axis centered in the first opening, an actuating portion including rearwardly facing gear teeth arranged in an arc having a radius centered on the axis through the center of the first opening engageable with gear teeth on the contact support for rotating the contact support to the two positions, and detent means yieldably maintaining the actuator in either of two selected positions, an adjustment knob positioned on the operating portion of the actuator on the front side of the cover, and a pilot light assembly positioned in the second chamber.
 12. The switch assembly as recited in claim 11 wherein the pilot light assembly includes a pair of terminals respectively positioned by the side walls of the housing and positioned at opposite sides of an axis perpendicular to the rear side through the second opening, a receptacle for the pilot light positioned at the open side of the second chamber, a pilot light positioned in the receptacle to have terminal portions engaging the terminals within the chamber and a bulb portion extending through the second opening in the cover, and a lens providing a cover for the second opening in the cover.
 13. An electric switch assembly that is selectively usable with either of two switch covers with a first of the two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the cover on centers X inches apart and a second of the two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second cover on centers Y inches apart and wherein X is less than Y, said assembly including: a selected one of the two covers, said selected cover having a front side and a rear side, a molded housing mounted adjacent the rear side, said housing having a pair of parallel side walls spaced equidistantly on opposite sides of an axis through the centers of the openings and a rear wall extending between the side walls providing the housing with a first open-sided chamber that extends rearwardly of a first of the pair of openings in the selected cover and a second open-sided chamber that extends rearwardly of a second of the pair of openings in the selected cover, a pair of slots in the side walls of the first chamber extending in a plane perpendicular to the side walls and parallel and spaced (X+Y/4) inches from an axis perpendicular to the rear side through the center of the selected cover, a pair of stationary contacts positioned by one of the side walls in spaced relation on opposite sides of the plane in the first chamber adjacent the said one side wall of the chamber, A movable contact assembly in the first chamber, said contact assembly including a movable support having a contact support portion positioned by the pair of slots in the first chamber for rotation about an axis perpendicular to the plane between two positions and an actuating portion spaced a predetermined distance and extending parallel to the plane, said actuating portiOn having gear teeth thereon arranged in an arc having a radius centered on the axis of rotation of the support and facing the rear wall of the selected cover, and a movable contact carried by the support and engaging the pair of stationary contacts when the support is at a first of its two positions and spaced from the stationary contacts when the support is at a second of its two positions, an operator assembly comprising: a selected one of a pair of plate-like members usable selectively with the two switch covers with a first plate-like member mounted on the open side of the first chamber when the first cover is the selected cover to have an opening therein centered on the axis through the center of the first opening in the first cover and with a second plate-like member mounted on the open side of the first chamber when the second cover is the selected cover to have an opening therein centered on the axis through the center of the first opening in the second cover, an actuator positioned on a front side of the selected plate-like member, said actuator having an operating portion extending through the first opening and rotatable about the axis centered in the first opening and an actuating portion rotatable on the rear surface of the selected plate-like member and including rearwardly facing gear teeth arranged in an arc having a radius centered on the axis through the center of the first opening and engageable with the gear teeth on the contact support for rotating the support to its two positions when the operating portion is rotated to two positions, means including a detent on the operating portion and a pair of spaced openings in the plate-like member for resiliently maintaining the operating portion against rotation from either of the two positions and an operating knob positioned on the operating portion on the front side of the cover.
 14. The switch assembly as recited in claim 12 including a pilot light assembly positioned in the second chamber, said pilot light assembly including a pair of terminals respectively positioned by the side walls of the housing at opPosite sides of an axis perpendicular to the rear side through the center of the second opening, a receptacle for the pilot light positioned at the open side of second chamber, a pilot light positioned in the receptacle to have terminal portions engaging the terminals within the chamber and a bulb portion extending through the second opening in the cover, and a lens providing a cover for the second opening in the cover.
 15. The switch assembly as recited in claim 13 including a second pair of stationary contacts positioned by the other of the pair of side walls on opposite sides of the plane in the first chamber adjacent the other of said pair of side walls, and a second movable contact carried by the support and engaging the second pair of contacts when the support is at the second of its two positions and spaced from the second pair of stationary contacts when the support is at the first of its two positions.
 16. The switch assembly as recited in claim 15 wherein the means for resiliently maintaining the operating portion against rotation includes a third opening in the plate-like member which is engaged by the detent and maintains the operating portion in a position intermediate the two positions and the first and the second movable contacts in spaced relation to their associated stationary contacts.
 17. The switch assembly as recited in claim 15 wherein the operating portion is selectively positionable in either of two maintained positions relative to the actuating portion of the actuator and the plate-like member includes saId pair of spaced openings which resiliently maintain the operating portion against rotation from either of two positions when the operating portion is in one of its selected positions relative to the actuating portion and a set of three spaced openings which resiliently maintain the operating portion against rotation from either of three positions when the operating portion is in the other of its two selected positions relative to the operating portion.
 18. An electric switch assembly that is selectively usable with either of two switch covers with a first of the two covers having a pair of openings therein spaced equidistantly a predetermined distance apart on opposite sides of a center of the cover and a second of said two covers having a pair of openings therein spaced equidistantly on opposite sides of a center of the second cover a predetermined distance apart with the distance between the openings in the first cover being less than the distance between the openings in the second cover, said assembly including: a housing mounted adjacent a rear wall and rearwardly of the pair of openings in a selected one of the pair of covers, said housing having an internal cavity with said cavity having an open side facing the rear wall, a center located on an axis extending through the center of the cover and portions extending rearwardly of the openings in the cover, and a pair of movable contact carriers in said cavity spaced equidistantly on opposite sides of the center of the cavity and movable in parallel planes with said planes spaced apart a distance greater than the distance between the center of the openings in the first cover and less than the distance between the center Of the openings in the second cover. 